The White House is seething. Donald Trump has branded a House resolution to limit his Iran war powers as 'unpatriotic'. A direct challenge from his own party. The vote, largely symbolic, saw eight Republicans cross the floor. A warning shot.
Downing Street is watching carefully. The UK has today reaffirmed its commitment to the Joint Comprehensive Plan of Action (JCPOA). A stark contrast to Washington's maximalist pressure campaign. Boris Johnson is treading a careful line. He wants to keep the deal alive, but cannot afford to alienate Trump.
Inside the Lobby, the whisper is that British diplomats are working overtime. They are trying to broker a 'Trump-plus' deal. Something that satisfies the US concerns about Iran's missile program, but keeps the original framework intact. It is a long shot.
The backbench mood is nervous. Labour MPs are demanding the government publicly break with Trump over Iran. They smell blood. But Johnson knows the electoral calculus. He cannot be seen as weak on defence.
Polling data suggests the public is wary of another Middle East conflict. Only 23% support UK involvement in any US-led military action against Iran. That number drops further if it is seen as unilateral. Downing Street has taken note.
The next 48 hours are crucial. Trump's rhetoric is escalating. The UK is trying to thread the needle. But the margins are razor thin. In Whitehall, they are preparing for the worst: a full-blown crisis that could tear the special relationship apart.
One senior diplomat put it bluntly: 'We are in the last chance saloon. If Trump pushes for war, we are out.' The game is on.
